National Development Group for Educational Innovation & Sumagaysay, L. S. (1980). In-service education for primary teachers: Design formulation. National Development Group for Educational Innovation.
Chicago-viite (17. p.)National Development Group for Educational Innovation ja Lourdes S. Sumagaysay. In-service Education for Primary Teachers: Design Formulation. Manila: National Development Group for Educational Innovation, 1980.
MLA-viite (9. p.)National Development Group for Educational Innovation ja Lourdes S. Sumagaysay. In-service Education for Primary Teachers: Design Formulation. National Development Group for Educational Innovation, 1980.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.